Dust cover jettisoned from Kepler telescope
The spacecraft's photometer can now see the stars and will soon start the task of detecting planets.
Provided by the Jet Propulsion Laboratory, Pasadena, California
April 8, 2009
Engineers have successfully ejected the dust cover from NASA's Kepler telescope, a space mission soon to begin searching for worlds like Earth.
"The cover released and flew away exactly as we designed it to do," said Kepler Project Manager James Fanson of NASA's Jet Propulsion Laboratory, Pasadena, California. "This is a critical step toward answering a question that has come down to us across generations of human history — are there other planets like Earth, or are we alone in the galaxy"?
Kepler, which launched March 6 from Cape Canaveral, Florida, will spend 3.5 years staring at more than 100,000 stars in the Milky Way Galaxy for signs of Earth-size planets. Some of the planets are expected to orbit in a star's 'habitable zone,' a warm region where water could pool on the surface. The mission's photometer contains the largest camera ever flown in space — its 42 charge-coupled devices (CCDs) will detect slight dips in starlight. This occur when planets passing in front of their stars partially block the light from Kepler's view.
The telescope's oval-shaped dust cover, measuring 67 inches by 52 inches (1.7 meters by 1.3 meters), protected the photometer from contamination before and after launch. The dust cover also blocked stray light from entering the telescope during launch — light that could have damaged its sensitive detectors. In addition, the cover was important for calibrating the photometer. Images taken in the dark helped characterize noise coming from the instrument's electronics. This noise will later be removed from the actual science data.
"Now the photometer can see the stars and will soon start the task of detecting the planets," said William Borucki, Kepler's science principal investigator at NASA's Ames Research Center in Moffett Field, California. "We have thoroughly measured the background noise so that our photometer can detect minute changes in a star's brightness caused by planets."
At 10:13 p.m. EDT April 7, engineers at Kepler's mission operations center at the Laboratory for Atmospheric and Space Physics, Boulder, Colorado, sent commands to pass an electrical current through a 'burn wire' to break the wire and release a latch holding the cover closed. The spring-loaded cover swung open on a fly-away hinge before drifting away from the spacecraft. The cover is now in its own orbit around the Sun, similar to Kepler's Sun-centric orbit. See an animation of the event below.
With the cover off, starlight is entering the photometer and being imaged onto its focal plane. Engineers will continue calibrating the instrument using images of stars for another several weeks, after which science observations will begin.
Image credit: NASA/Ames/JPL-Caltech